A desktop computing device usually offers two basic input devices: the keyboard and the mouse. Text input is provided through the keyboard, while pointing (moving pointer, selecting) as well as most window management actions (resizing, scrolling, menu selection, etc.) are executed with the mouse. There is also some redundancy, since the keyboard can also control navigation (arrow keys) and some window manager actions (with shortcut keys).
On a handheld device a touch sensitive area on the display is commonly used as the only or primary input interface. The total display area on such a device may be shared for display, text entry and application icons. The size of such a display limits the user's ability to easily enter data and limits the ability to have an easily usable dedicated area for text input. On such devices that use a dedicated input area, it's size may be too small to be accurately accessed by finger. In such cases, a stylus is used to enter text.